There was some discussion about using >10V, and I think it should be ok, since also the charger is giving higher voltage for the bus. Could be, that the actuator don't last as long with 12V then 9V or something.
My plan is to run my bioloid with 3-cell LiPo. As said earlier, when fully charged this gives you 12.6V. Also, you _must_ cut the power when the voltage drops to 9V.
So, this way I'll have range from 9-12.6V, which seems quite nice from both battery and bioloid point of view. Only piece of electronics I need is a circuit to cut the current when voltage drops to 9V (and maybe a fuse). No regulators, no capacitors.
There is absolutely no point in using _regulated_ voltage for the bioloid 3-wire bus. That's just waste of energy. Especially, since my understanding is that ax-12s adjust to the voltage they get. So, if you tell them to move at certain speed / set torque etc, it will be the same if the voltage is 10V or 8V.
Also remember that the voltage on LiPo drops almost linearly. So, you must make use of as wide range as possible, or else you'll only get current for very limited time.
I bough a dc/dc converter which gives me 9-18V -> 5V regulated for the electronics (something like >80% efficiency). I also have a 3.3V linear-regulator which is needed for few components, like my cameras.
Some one asked if the LiPo can provide enough current. Oh yes, they're a lot better then nimh etc batteries. Many of them can provide something like 20A of constant current, with peaks up to 30A or 40A. So with this solution you would not even need the capacitors etc which cm-5 has to make sure there's enough current for the actuators.
NullARC wrote:
I think our Bioloid's are going to be wearing backpacks!!
Mine will
Not for the battery, but electronics. Most of the LiPos are really long in one dimension. My plan is to build a bit higher torso for the robot, where I could fit 2 of these (rather in the center of the torso, not back, to keep the gravity center in the middle)http://www.verticalhobby.com/kauppa/pro ... ucts_id=59 (click English flag in the lower right corner).
inaki wrote:
According to my own tests the power supplied to AX12s by CM5 is 9.6-9.8Volts. I get the same results with two instruments.
But this is when you're running it with battery, right?
Pev, thanks for the info on the fuse. I was meaning to ask about it or try to figure it you myself. If the fuse is rated 5A, and it sits between battery and everything else, I have 2 questions:
1) I guess the current in the bus can be higher then, 'cause of the capasitors?
2) So is there no fuse protecting the system, when you run the bioloid with the charger?
Cheers, and good luck for my fellow roboteers for the 2007
-- Juha
Statistics: Posted by Juha — Mon Jan 08, 2007 11:33 am
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I'll need 3 though. Only about $80.00!
) The Li-Po or Li-Ion batts will extend the Bioloid's run time and reducing the weight will also lend to longer run times. This could also lead to the ability to build larger robots with more actuators. Very cool! I will keep researching this subject as much as I can. Please keep us updated Pev!